1. Technical Field
This disclosure relates to pressure relief valves.
2. Background Art
In the subsea industry pressure relief valves with relatively low cracking pressures are often used as a safety device to prevent the buildup of inside pressure within a subsea electronics housing. Subsea housings are hydrostatic pressure vessels designed for external pressure and are typically not capable of withstanding even modest relative internal pressure without failure.
Significant Internal pressures can develop as the result of hydraulic leaks, battery off-gassing and or slow sea water leaks that cannot relieve internal pressure quickly enough during recovery to the surface.
Unfortunately pressure relief valves have a reputation for poor reliability in the subsea environment. Corrosion and fouling of the moving parts by suspended particulate matter can sometimes lead to failure by preventing the valve from reseating sufficiently to establish a reliable seal. While the use of redundant corrosion resistant materials and seals improve reliability of subsea pressure relief valves these enhancements do not address the fundamental problem of the mechanical parts within the valve; each being single point of failure.